按网络所连接地区的大小和距离可以将计算机网络分为()

A、以太网和令牌网

B、环型网、星型网、总线型网

C、局域网和广域网

D、同种机网络和异种机网络

If it is left ______, this fast-spreading disease is likely to affect millions of Asian and African children, including more and more injured grown-ups.

A．unchecked

B．uncontrolled

C．transmitted

D．contaminated